1. Field of the Invention
The present invention relates managing defects in optical recording/reproduction, and more particularly, to a recording medium on which audio and/or video (A/V) data is recorded, stores additional information for defect management, and to a method for managing defects.
2. Description of the Related Art
When data is recorded on a rewritable medium such as a digital versatile disc random access memory (DVD-RAM), the medium may be damaged due to repeated writings and readings, thereby reducing the life of the medium. Furthermore, defects may be caused by fingerprints, scratch or dust.
The above defects cause loss of the data which is recorded on the medium. Therefore, data stored in an area that may become damaged must be moved to an area that is not damaged, and the area that may become damaged is no longer used. This process is called defect management. However, typical defect management in which data of a defective area is moved to another area when A/V data, different from computer data, is recorded on the rewritable medium, causes physical discontinuity of the recorded data which results in a negative influence on real-time recording and reproducing of the A/V data.
The defect management of a typical DVD-DRAM will be described with reference to FIGS. 1 and 2. Referring to FIGS. 1A and 1B, slipping replacement is a defect management method used for managing a defective area found in initialization of a disc (i.e., when the disc is formatted). A user area is a freely rewritable area of the DVD-RAM disc, and a spare area for defect management is controlled by a system, and thus it cannot be arbitrarily used by a user.
A physical sector number coincides with a logical sector number in a bare disc shown in FIG. 1A. When data is recorded on the empty disc, i.e., the disc is formatted, defective sectors m and n shown in FIG. 1B are not used in a process of defect management for checking whether the user area has an error. No logical sector numbers are assigned to the defective sectors m and n, so that the disc is processed as not having any defective sectors. Further, a portion of the spare area having the size corresponding to the size of the defective sectors is used to record the data. Positions of the defective sectors are recorded on a primary defect list (PDL) area of a system area of the disc to be managed defects.
Meanwhile, linear replacement as shown in FIG. 2 is for the defect area found in the process of defect management when data of a desired program (or title) is recorded on the disc where data is recorded. That is, in linear replacement, the spare area is replaced with logical sector numbers assigned to error correction code (ECC) blocks (here, m and n data blocks) having the defective sectors, to record corresponding data to be recorded on the defect area position. Here, the ECC block is a data block of a 16 sector unit. Also, information for the defective ECC block includes a start sector number of the ECC block having a corresponding defective sector and a start sector number of the ECC block of a replaced spare area, and the information is recorded on a secondary defect list (SDL) area of the system area of the disc.
However, by the defect management method, in which the defect area shown in FIG. 2 is replaced with the spare area, physical discontinuity is generated when the A/V data is recorded and reproduced, is not conducive to real-time recording and reproducing. That is, if the A/V data is recorded or reproduced on the user area where the defect management process has been performed, data arriving at a defective block m is sought to a replacement block m located in the spare area and then recorded and reproduced, and further sought to a next block of the defective block m of the user area to be resumed recording and reproducing, so that seek time is twice as long for one defective block, which is not conducive to real-time recording and reproduction of A/V data.